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Summary

Underground reservoirs associated with the Brunel Pumping Station, Star Cross.

Location

Protected Status

• Listed Building (I) 1097684: THE STARCROSS PUMPING HOUSE

Other References/Statuses

• National Monuments Record: 447997

Monument Type(s) and Dates

• RESERVOIR (XIX - 1845 AD to 1848 AD (Between))

Full description

Pink, F., 2014-2015, South Devon Coast Rapid Coastal Zone Assessment Survey Desk-Based Assessment (Interpretation). SDV357736.

R. B. M., 2018, Underground Reservoirs at Starcross Pumping House: Historic Buuilding Record (Report - Survey). SDV361957.

Wessex Archaeology was commissioned by BAM Nuttall Ltd to produce an Historic England Level 2 historic building record (HBR) of an underground reservoir beneath Starcross Fishing and Cruising Club car park. The reservoir is associated with the adjacent mid-19th century Grade 1 Listed Starcross Pumping House, which was part of the South Devon Railway (SDR) constructed
in the mid-1880s by Isambard Kingdom Brunel.

The Starcross Pumping House stands on the east side of The Strand, Starcross, near Exeter. The car park with the underground reservoir lies south of the Pumping House, centred on OS NGR 297753 081742. The historic building record was required as the feature was recently uncovered during part of ground works related to the flood defence scheme led by the Environment Agency. Due to the confined access to the reservoir, consisting of a single circular opening, the survey used a combination of Ground Penetrating Radar (GPR), terrestrial laser scanning and photography to produce a descriptive record of the reservoir both for heritage purposes and to inform on-going engineering decisions related to the future of this historic feature. The survey results have been able to produce an accurate model of the reservoir and establish its true location and overall size. The first railway was designed with the atmospheric system in which the air is pumped from a continuous cylinder in the centre of, in this case, broad gauge track. In order for this to happen, steam engine pump houses were built along the line at regular intervals. The reservoir supplied the boilers at Starcross for the steam to power the pump beam engine. The atmospheric railway lasted for approximately a year between 1847 and 1848 before being converted to conventional broadgauge steam locomotive system. The reservoir at Starcross has been built below ground level a distance to the south from the boiler house at Starcross. It consists of a large rectangular feature consisting of two stone-built arched chambers covering an area of 318 square metres. These are separated by a central stone dividing wall with a series of ten open arches. Digital survey has also recorded associated features within the chamber such as possible iron ladder fittings and circular holes, most now covered for probable venting.

The South Devon Railway Company built and operated the railway from Exeter to Plymouth and Torquay in Devon. It was a 7ft ¼ in (2.14m) broad gauge railway built by Isambard Kingdom Brunel. The line had to traverse difficult hilly terrain, and the company adopted the atmospheric system in which trains were drawn by a piston in a tube laid between the rails, a vacuum being created by stationary engines. The company operated from 1846 to 1876 when it was taken over by The Great Western Railway (after Wikipedia article).

The atmospheric pipe was laid in the centre of the single broad gauge track. In crosssection it was not quite a complete circle, a continuous slot was formed in the top of the pipe to pass the bracket of the piston. A 13 inch pipe was to be used between Exeter and Newton, with 15 inches generally being specified west of there, but 22 inches on the inclines.

The stationary steam engines were 40 hp (30 kW) vertical engines operating in pairs. 12 hp (8.9 kW) auxiliary engines were provided at each engine house for water pumping and other purposes. The engine houses were located at intervals of about 3 miles (4.8 km), and had a chimney in an Italianate style. The first four to Starcross were built in red sandstone, and later houses in grey limestone. Pumping was intended to create a vacuum of 15 inches (381 mm) of mercury, but leakage of the valve forced a higherdegree of vacuum, to 20 inches (508 mm), to be created at the pump to create adequate vacuum at the remote end of the pipe section.

The piston carriage appears to have been a covered van. The piston was suspended from a bracket under the piston carriage, on a 20-foot (6.1 m) long beam, with a counterweight for balance. It was capable of being raised and lowered, so that at station areas it could be lifted clear. It was not possible to run the tube through pointwork. At some stations an 8-inch (203 mm) auxiliary pipe was provided at the lineside, from which the train could be towed by rope, but in many cases, it is likely that horses were used for shunting and marshalling, and human power to move individual vehicles.

Pumping to evacuate the pipe started between 5 and 8 minutes before the time a train was expected to enter the pipe section. For a long period, there was no electric telegraph communication, so that the pumping had to start before the scheduled entry time; in the event of late running this meant wasted pumping. (The telegraph was commissioned on 2 August 1847; Brunel had inexplicably delayed its installation, and even now did not allow its use at night).

The dates of the first running are inconsistent between commentators but, it is generally agreed that the atmospheric system ran for approximately one year between 1847 and 1848. Throughout the early stages of the Company's existence, there had been doubters about the atmospheric system; and these people were often vociferous when some setback or failure was reported. The alarming news was revived that on 4 May 1847 the London and Croydon Railway had decided to abandon the atmospheric system on their line, due to insuperable technical problems.

At a Board meeting on 28–29 August, Brunel suggests that Samuda (who still had contractual obligations to ensure effective operation of the system) might be unable to putmatters right, and by the end of the second day the Board had decided to terminate the affair. The shareholders' meeting took place on 29 August 1848 and it now seemed that everyone was against the atmospheric, and a stormy meeting approved the suspension of the use of the system unanimously. In fact, the decision was to suspend until Samuda put the system into working order, but it was obvious he was not in a position to do so, and the last atmospheric train was an up goods arriving at Exeter at 12:30 in the small hours of Sunday 10 September 1848.

The atmospheric system was at an end on the South Devon Railway. The atmospheric engine houses were shut up and never worked again. £433,991 had been spent on equipment for the system.

Description of Underground Reservoir.
Given the restricted nature of the feature and the single narrow access point much of the following description is based on observation from the surface. At the time of the survey the immediate area was open and left at formation level for the new carpark. The original car park level was to be reduced and re-cast in reinforced concrete. The discovery of the opening and the top of the east chamber stone arch forced a halt to site excavation. There was no permitted access into the chamber for health and safety reasons.

Survey and measurements are produced from GPR and internal laser scanning of the east reservoir. From the results of the survey it was found that the underground reservoir consists of an east and west chamber with a central dividing wall. The main axis of the reservoir is just off north-south and followed the Strand road directly to the west. It was only possible to survey the interior of the east chamber with the laser scanner but the GPR survey covered most of both chambers from the surface.

East Chamber
Access to the east chamber of the reservoir was via a circular aperture at the north end (Figure 1, Plate 1). This measured 0.80m in diameter and was deliberately formed within the stone arch of the chamber so it is considered an original feature. There were no surface signs of fixings for a hatch. The arch was 0.35m thick and was constructed from a single course of large roughly hewn stones set in hard mortar (Plate 2). A consistent arch profile was recorded along the whole length of the east chamber (Figure 2). The laser scan highlighted another similar sized circular opening approximately mid-way along the top of the east chamber arch from the interior data (Figure 2). It is possible that there are a series of these openings along each of the chamber arches. Not visible from thesurface, there may be a third such opening at the south end of the east chamber. Possibly originally used as vents for any gas that might build up in the chambers, it is assumed that this pattern of three openings per chamber is mirrored on the west chamber.

The internal vertical walls of the chamber were constructed from squared large blocks of stone laid in random courses and in various sizes. The mortar appeared to be cementitious in nature but, due to the surface of the walls being covered in dirt and slime, this could not be accurately determined (Plate 3).

Visible on the internal south face of the north wall of the east chamber were the remains of several iron fixings. It is thought that these features originally supported an iron ladder due to their proximity with the access hole. The iron fixings are a mixture of loops and flat bars with hook ends (Plates 3-4). It is also possible that the loop fittings held a draw pipe. Water would need to be pumped into the boilers to the north and, as yet, no clear evidence of this has been found.

In plan, the reservoir would appear to have symmetry (Figure 2). The east chamber is basically rectangular in plan and measures 32.50 m in length north-south and 4.43 m wide east-west. The east chamber is separated from the west chamber by a wide dividing wall with ten equally spaced arches along its length. Only the very tops of the arches were visible due to the depth of the water. The width of this wall has been established via the GPR survey to be 1.5m thick. The GPR data suggest that the arches are open-ended into each of the chambers.

The north-east and south-west corners of the east chamber are rounded but, where the north and south walls of the east chamber meet with the central dividing wall, the corners are squared. Laser scan data has identified a curious ‘step’ at the south end (Figure 2) of the east chamber. It is located approximately 6.47 m from the south wall of the east chamber. The scan data suggests an irregular edge profile to the step, but the feature is generally straight and crosses the east chamber from east to west at a very slight angle. It is not known what this feature represents as it stands approximately 0.06 m above the present water line. The water level in the east chamber is 1.36 m deep with the full depth of the chamber at 3.20 m below the top of the arch.

In cross section the reservoir is double arched with central dividing wall approximately 0.90m wide (Figure 3). It is assumed that both arches spring from the centre wall and also the outside east and west walls. Present water level is just below the tops of the dividing wall arches. The east chamber would appear to be basically intact; however, there are a series of anomalies mainly at the south end. The ‘step’ mentioned above has a corresponding anomaly in the arch directly above (Figure 2). The laser scan data, although greatly reduced at this end due to distance and stalactite interference, shows a ‘line’ in the arch stones. Between the second and third centre wall arches the wall is slightly wider (Figure 2). This may be due to construction differences, but the location corresponds with the location of the ‘step’ in the east chamber. A further anomaly is found in the GPR data for this location (Figures 4 to 6). This has recorded a large void over the same spot but, above the arches. This may be coincidence, or it may relate to structural issues as yet not fully understood; it may therefore be deliberate and have some bearing on the functioning of the reservoir system. (See report for full details).

Sources / Further Reading

SDV357736	Interpretation: Pink, F.. 2014-2015. South Devon Coast Rapid Coastal Zone Assessment Survey Desk-Based Assessment. AC Archaeology Report. Digital.
	Linked documents:1
SDV361957	Report - Survey: R. B. M.. 2018. Underground Reservoirs at Starcross Pumping House: Historic Buuilding Record. Wessex Archaeology. 205291.03. Digital.

Associated Monuments

Associated Finds: none recorded

Associated Events

• EDV7652 - Historic Building Recording: Underground Reservoirs at Starcross Pumping House (Ref: 205291.03)

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